Presently walls in residential and commercial structures are finished using wall board which is generally screwed or nailed to vertical wooden and/or metal studs, the gaps between the individual boards are covered with a joint reinforcement which is either a paper and/or a mesh and thereafter a drywall compound is applied thereon. In this patent application the words wallboard and/or drywall are used interchangeably to mean the same thing, namely gypsum board which is covered with paper and used for creation of walls prior to drywall compound being applied.
Of particular importance is the finishing of internal corners which are created at the juncture of two wallboards coming together at a corner location.
Presently a gap usually exists between the two wall boards which abut each other at the corner. In order to bridge this gap to prevent future cracking of the drywall compound a layer of paper and/or mesh is applied into the corner and thereafter the drywall compound is liberally applied for subsequent sanding.
The present device relates to the tool and mechanism used for sanding of the drywall compound after the joint paper and the drywall compound has been applied and dried.
There are a number of prior art devices and in particular U.S. Pat. No. 6,325,708 by Jody W. Miles filed on Sep. 28, 2000 and issued on Dec. 4, 2001 titled Device for Sanding a Drywall Corner describes and teaches a corner sander including a base made up of left and right planar wall members which meet at a juncture and/or as in our case at the tip and form a generally v-shape support for the abrasive media to be placed there upon. The V-shaped support is so designed that the sanding pad more aggressively sands the areas in and around the juncture (the tip) of the base and less aggressively sands the areas of the corner away or outwardly from the juncture or the tip. They further explain in the specification and also in the claims that in order to achieve this function the opposed first left and right members which are called “walls” preferably assume angles of slightly less than 90 degrees.
There device and geometry is best shown in FIG. 4 of the U.S. Pat. No. 6,325,708 specification and is schematically reproduced in our FIG. 2 in which it is apparent that the corner of the sanding base aggressively impinges into the wallboard corner and the left wall and right wall of the base creates a large gap on one side of the corner and a smaller gap on the other side of the corner due to the angular relationship between the left wall and right wall being less than 90 degrees.
Referring to FIG. 3 the resulting sanding profile after the tool has been used to smoothly sand away the drywall compound may result in either paper thinning as depicted in FIG. 3 on one side and/or ridges and/or valleys occurring on the other side.
Those trained to finish wall board, wall surfaces and corners will know that it is undesirable to impinge upon the paper since this produces a rough surface finish which is not aesthetically pleasing to the end user.
In addition, it is desirable to have a smooth corner transition and surface free of ridges and valleys and free of paper thinning as depicted in FIG. 3.